Directional gyro



June 19, 1945. CARLSQN 2,378,829

DIRECTIONAL GYRO Filed June 29, 1943 5 Sheets-Sheet l INVENMR.

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Patented June 19,1945

Bert G. Carlson, Erieside,

Ohio, assignor, by

mesne assignments, to Jack & Heintz, Inc., Cleveland, Ohio, a corporation of Ohio Application June 29, 1943, Serial No. 492,671

Claims. (01; 244-48) This invention relates in general to automatic pilots and more particularly to improvements in directional gyros therefor.

In the conventional automatic pilot the rate of turn of the aircraft 7 is variable with the amount of turnwhich may be set in the automatic pilot by the aviator. If, however, a large is set in, the automatic pilot throws the rudder hard over causing a high rate of turn so as to not be directly under the control of the aviator.

One of the primary objects oige present invention is to provide a new and 11 e1 simple and efiicient means whereby definite and variable rates of turn may be set up at the will of the aviator by the turning of one control knob and the starting and stopping and direction of turn controlled by the turning of another control knob, so that the direction and rate of turn is independent of the amount of turn desired and is the aviator.

With the foregoing and other objects in view, the invention resides in the combination of parts and in the details of construction hereinafter set forth in the following specification and appended claims, certain embodiments thereof being illustrated in the accompanying drawings, in which:

Figure 1 is a view in side elevation of the directional gyro assembly with the box shown in vertical section;

Figure 2 is a partial view in front elevation of the directional 1 the direction and rate of turn control knobs;

Figure 3 is a side view of the same with? the side cover partly broken away, and showing the rate control geartrain in dotted lines;

Figure 41s a view in longitudinal section taken through the direction control means, along-lines 4-4 of Figure '2;

Figure 5 is a rear end view of that shown in Figure 4;

Figure 6 is a view in section taken along line showing the valve and control means for the direction of tum control; and

Figure 7 is a view in longitudinal section taken along line 1-1 of Figure 2 of the rate control knob and clutch.

Referring more particularly to the drawings, the directional gyro I may be of conventional form and enclosed in a. casing 2 from which air The gyro assembly includes a compass card 3 and a follow-u or rudder position card 4. In addition to the conventional caging control knob, there are provided a control knob 6 with left, righ and neutral gyro, showing the cards and moved to the right and or off" positions for initiating and controlling the direction of desired turn and a control knob 1 for controlling the rate of turn once it is initiated by operation of knob 6.

In order to predetermine and control the direction of turn an air actuated turbine 8 is mounted on a shaft 9 for rotation in either direction, the admission of air to the turbine being under the control of hand knob 6. This is brought about by a piston l0 slidably arranged within a cylinder II and normally balanced in the neutral central position shown in Figure 6 by two opposed coil springs 42 and I3 removably retained in the cylinder by screw plugs l4 and IS. The piston is releasably locked in this neutral position by having its central portion enlarged and provided with a flat portion iii of maximum diameter to receive a ball ll rotatably and slidably carried by the cylinder and which ball, when the piston is in the neutral position, as shown in Figure 6, also engages one of the peripheral buckets of the turbine 8 to stop any rotation of the turbine in either direction. The piston is further held in normal neutral position by the normally balanced pressure of air from the two air inlet tubes 20 and 2| leading through passages 22 and 23 into cylinder chambers 24 and 25 on either side of the piston and also leading through jets i8 and I9 to the turbine buckets.

Air is drawn in through tube 26 into the valve casing 21 in which is located a valve -28 urged forwardly by a compression coil spring 29 arranged about the valve stem 30 to which is secured the control knob 6. When the control knob is in the 011', or neutral position, as shown in Figure 2, the 'valve is'in such a position as to admit a fullflow of air from inlet tube 26 into the valve casing 21 and out through tubes 20 and 2| to the already described in connection with Figure 6.

When, however, it is desired to make a turn to the right or left, such turn may be initiated by a corresponding manual turning of the control knob 6 to the right or left. If turned to the left for a left turn the valve 28 is moved to cut oif the supply of air to tube 2| and the jet I9. Accordingly thereis an overbalance of pressure in piston chamber 24 causing piston ID to be ball I! rides downwardly on the incline of the piston into a pocket 3| and the ball is thus removed from locked engagement with the bucket of the turbine 8. The stream of pressure air through tube 20 and jet l8 impinges on the turbine buckets to rotate the turbine in a counterclockwise direction. Upon a piston and turbine, assembly 'gimbal in one direction or manual turning of knob is in the opposite direction for a right turn, tube 20 will be closed and tube 2| opened and air will be cut off from jet I8 but supplied to jet l3 to spin the turbine 8 in a clockwise direction as ball rests in pocket 3|, A return of knob 8 to neutral position opens the valve with respect to tubes 20 and 2| and equalizes the flow of pressure air through these tubes to jets l8 and i9 and through passages 22 and 23 to chambers 24 and 25, whereupon springs 12 and I3, being balanced, return the piston so that portion I5 is in alignment with-ball H, which latter engages a bucket 'of turbine 8 in 'locked engagement in neutral position.

The rate of turn is under the control of the manual knob I which is connected through a spring clutch to the conventional rudder synchronizing shaft 32. This shaft carries at its other end a ring gear 34 meshing with gear 35 carried by a shaft 36. Gear 35 meshes with agear 38 carried by a shaft 31 which also carries a ear 39 which meshes with a gear 33 carried by a shaft .40 which also carries a gear 4| meshing with a carries a worm 68 that meshes with a gear 8| of a differential. The rotation of gear 8| effects a rotation of gears 62 and 83 without rotation of gear 64. Gear 83 meshes with a conventional air valve gear 85. This air valve gear 65 corresponds to the gear 23 shown in the U. S. patent to Bert G. Carlson, No. 2,155,401, dated April 25,

1939, for Rate control course changing means for automatic pilots, and as explained in this patent, the purpose of gear 85 is conventional in that it turns the top card 4 and also carries the usual air pick-offs and thus disturbs their relationship with the usual shrouds carried by the the other to correspondingly initiate a turn. One pick-off bec omes closed while the other is opened. This activates the usual air relay to operate the usual balanced oil valve to actuate the conventional hydraulic servo to move the aircraft rudder in one direction or the other, in accordance with the usual practice. Likewise, the shaft 56 is the follow-up shaft corresponding to that shown at It in the above Carlson patent. However, this shaft 86 carries a bevel gear 81 meshing with gear 68 carried by a shaft 69. The shaft 69 also carries a gear I meshing with gear 84 of the differential. Rota tion of gear 84 by the usual follow-up shaft 36 rotates gear II and through pinion gears I2 and 13 rotates gears 62 and 63 to rotate valve gear 85 without rotation ofgear As stated before, a. clutch is interposed between the rate control knob I and the rudder syngifronizing shaft 32 the effect of which is to re ate the speed at which the shaft may be rotated regardless of the air pressure exerted by air jet l8 or I! against the buckets of air turbine 8. This clutch includes to shaft 32 and a barrel screwed into the front wall of the box 2 and provided with a circular flange 52 to overlap and retain that of collar 49. A clutch. plate'53 is keyed at 54 to barrel 5| to prevent rotational movement but permit a limited longitudinal movement. plate 55 is provided and a compression coil spring 6|, worm 80 or shaft 58 interposed between plates 53 and 55. An adjustment set screw 53 is screwed into the hand control knob 1 which is screwedinto the barrel 5|. A set screw 56, locked in place by a lock screw 51, passes against plate 55 toinitially adjust the compression of spring 58 and consequently the clutch, or friction braking, effect: on: the. rotatability' of "shaft 32'.

' With the above described arrangement, a; tum-- ing of control knob I in a clockwise direction, as viewed in Figure 2, causes a compression of spring 58 to increase a resilient friction brakin effect on shaft 32 as plate 53 presses more tightly against collar 49. Accordingly, a-rotation of control knob 'l in a counterclockwise direction relieves the braking effect on the'rotation of shaft From the foregoing, the operation of the invention will be readily apparent. When the aviator desires to turn right at'a given rate, he first moves the control knob 8 from off to R." He

then turns control knob 1 to the. desired rate of turn on its scale. The airplane continues to turn at that rate until knob 8 is turned to off or 1 until knob 1. is turned back to zero which is done when the desired course change has been effected.

I claim:

1. In an automatic pilot for aircraft having a rudder, the combination with course maintaining means, a controller including a shaft at said means for controlling the rudder, an air turbine and a train of reduction gears between the turbine and the controller shaftto cause the turn, ing of the aircraft, air jets for driving the turbine in either direction desired and a spring balanced piston carrying a means for releasably locking the turbine against 'rotation, manual valve means for diverting air to unbalance said piston to release said locking meansto drive said turbine in either direction and a variable drag means independent of the turbine for regulating the speed of rotation of said, turbine.

2. In an automatic pilot for aircraft having-a rudder, the combination with course maintaining means, a controller including a shaft at said means for controlling the rudder, an air turbine and a train of reduction gears between the turshaft said variable drag means including a spring a flanged collar 49 pinned at 58 friction clutch and a manual control for the effectiveness of the spring for adjustment of the clutch. a

- 3. In an automatic pilot for aircraft having a rudder, the combination with course maintaining means, a controller including a shaft at said means for controlling the rudder, an air turbine and a train of reduction gears between the turbine and the controller shaft to cause the turning of the aircraft, air jets for driving the turbine in either direction desired and a spring balanced piston with an enlarged center portion loosely carrying a ball to engage the peripheral buckets of said turbine to lock the same against rotation when the piston is in neutral central position, manual valve means fordiverting air to unbalance said piston and permit said ball to disengage itself from. said turbine so that the latter is air driven in either direction and a variable drag means independent of the turbine for regulating the speed of rotation of said controller shaft.

4. In an automatic pilot for aircraft having a rudder, the combination with course maintaining means, a controller including a shaft at said means for controlling the rudder, an air turbine and a train of reduction gears between the turbine and the controller shaft to cause the turning of the aircraft, air jets for driving the turbine in either direction desired and a spring balanced piston with an enlarged center portion loosely carrying a ball to engage the'peripheral buckets of said turbine to lock the same againstrotation when the piston is in neutral central position,

manual valve means for diverting air to unbalance said piston and permit said ball to disengage itself from'said turbine so that the latter is air driven in either direction and a variable drag means independent of the turbine for regulating the speed of rotation of said controller shaft, said variable drag means including a spring friction clutch and a manual control for the effectiveness of the spring for adjustment of the clutch.

means. a controller including a shaft at said means for controlling the rudder, an air turbine and a train of reduction gears between the turbine and the controller shaft to cause the tuming of the aircraft, air jets for driving the turbine in either direction desired and a spring balanced piston with an enlarged center portion loosely carrying a ball to engage the peripheral buckets of said turbine to lock the same against rotation when the piston is in neutral central position, manual valve means for diverting air to unbalance said piston and permit said ball to disengage itself from said turbine so that the latter is air driven in either direction and a variable 'drag means independent of the turbine for regulating the speed of rotation of said controller shaft, said variable drag means including a fric- BERT G. CARISON. 

